At present wireless local area networks are gaining wide recognition in the field of information science and video graphic communication for the purpose of transmitting and distributing data among multiple users located in one building (for example, among PCs, laptops, PDAs, printers and other users) without limiting the “mobility” of said users. Transmission of information with the use of WLANs reduces the cost of network because there is no need for laying connecting wires. A network of this type can be also used in cases when it is difficult or simply impossible to lay connecting wires and in cases when there are no socket connectors for local networks due to architectural limitations. WLAN is an ideal solution for companies and institutions in which users are often rearranged within premises. As a rule, existing WLANs are built based on the principle of equal rights of all network users, and radio communication in existing WLANs is arranged according to well-known international standards—e.g. standards IEEE 802.11, IEEE 802.11a, IEEE 802.11b and ISO 8802-11, HIPERLAN of type 2.
The distinguishing feature of WLAN consists in the fact that communication quality (and, hence, data transmission rate between two users) depends heavily upon a number of factors and in addition, communication quality is not constant in time. For example, the standards indicated above provide that four data transmission rates—11, 5.5, 2 and 1 Mbps—are to be used depending on communication quality. According to these standards, the rate of data transmission is to be set stage by stage, at first transmission is performed at a rate of 11 Mbps, and with poor quality of communication the rate of data transmission is decreased step-by-step. When the quality of communication between two users is very poor, data exchange is carried out at a rate of 1-2 M bps. Such a switchover from one data transmission rate to another one results in the increase in time of information transmission from one user to another.
Methods are known in which communication is arranged in a wireless local network between users, which are unable to transmit information directly to one another (See U.S. Pat. No. 4,987,536; EP Patent Nos. 0,481,171 and 1,117,270; Russian Patent No. 2,037,961 and PCT Patent Application Nos. PCT/SE00/00633 and PCT/US00/41180).
For example, in a known method for data transmission in a wireless computer network (See PCT Patent Application No. PCT/US00/41180) each of the users determines one or more “labeled routing trees”—i.e. shortest paths for communication links with other users. Then each user sends “labeled routing trees” (built by him) to other users who store them and then form the common “labeled routing tree” of the shortest path for data exchange with other network users based on stored individual “labeled routing trees”.
The known method, while providing for the transmission of messages to addressees by the shortest pathway, doesn't take into account the fact that in some sections of the selected route, the quality of communication may be not good enough, and, hence the rate of data transmission to users would be low.
It has to be pointed out here that when the quality of communication between a pair of users in WLANs built in accordance with the principle of equal rights for all network users is poor, there is often a third user, the quality of communication of which with both users from the said pair of users is good and who is capable of exchanging data with both of them at a rate of 5.5 or 11 Mbps.
It terms of the set of the most essential features, the closest analog to the invention claimed herein is the method for radio communication in a wireless local area network (See U.S. Pat. No. 6,115,580) that includes the determination of the quality of user-to-user links, with said quality being determined based on calculations of terrain information and location of users, storage of said calculated data on the quality of user-to-user links between all users and transmission of information to an addressee (out of the number of users located on information transmission route) who is characterized by good communication quality (calculated at the first stage).
The known method for selecting a route for transmitting information to an addressee based on calculated data on his current location doesn't allow one to take into account actual conditions of communication between users (presence of moving obstacles within WLAN operation area, radio interference/noise and the like).